Mesonlike baryons and the spin-orbit puzzle

I describe a special class of mesonlike ${\Lambda }_Q$ excited states and present evidence supporting the similarity of their spin-independent spectra to those of mesons. I then examine spin-dependent forces in these baryons, showing that the baryon spin-orbit puzzle is solved for them for the same reason spin-orbit forces are small for the analogous mesons: a fortuitous cancellation between large spin-orbit forces due to one-gluon exchange and equally large inverted spin-orbit forces due to Thomas precession in the confining potential. This solution provides a new perspective on spin-orbit forces in all baryons by showing that the three-body spin-orbit forces which were believed to be the origin of the baryon spin-orbit problem conspire in these states to become an essential part of this cancellation.